I tried editing /etc/fstab by hand twice but afterwards KDE would only load up to a black screen and mouse curser. Normally I would attribute that to a driver problem, but it happening twice on two separate reinstalls immediately after editing fstab seems like too much of a coincidence. But if there's no GUI tool, maybe somebody could please show me what the fstab entry should look like. On those attempts, I did sudo mkdir /mnt/data to create a mount point for the partition and made sure the owner was "raccoon."

Can you post the contents of your edited /etc/fstab.
The desktop not loading after enabling the automount is indeed very strange.
If this partition is mounted correctly and not somewhere in /home ikt should not make any problem.

On reboot, I was unable to get to a plasma desktop on either of the users. But I could access xfce and removed the edit. I still couldn't get to kde desktop on either users. So I reinstalled netrunner-desktop and netrunner-system. Now I can access the plasma desktop under "squirrel", but not "raccoon." That's not a big loss since I didn't do much customization yet anyway. It still doesn't explain why editing fstab should cause plasma to not load.

Success. Under the new username can get into the plasma desktop and df -aTh confirms the partition is indeed mounted. But "raccoon" still can't get to the plasma desktop with the partition automounted (even after deleting .cache and .kde) and that will have to remain a mystery.